There is no abstract but the concluding paragraph expresses the thesis of the article:

Accordingly, the postulation of a pre-existing, forty-member genealogy structured around Abraham, David, Josiah, and Joseph does more than merely solve a math problem. It also provides a window into the diversity of early Christological beliefs and one person’s attempt to reconcile various traditions and ideas about Jesus. However interesting the supposition of a pre-composed genealogy may be, it is not the final product. Matthew’s text is what must be explained, and there have been many attempts to count its generations. Of these, the least problematic is that Matthew double-counts David, just as the text tells us to do by reiterating David in v.17. David is thus the key to counting the generations in Matthew’s genealogy. Other attempts abandon the precise wording of v.17 in favor of a more ideally symmetric arrangement of three sets of fourteen. But this one misstep begets another, forcing exegetes to suppose additional complications—that our text is somehow missing a generation, that the author somehow alluded to the missing generation ever so subtly, or that Matthew somehow miscounted, even though the opening section is where authors ordinarily exercise the most care. Rather, the simplest solution is that Matthew tolerated a slight deviation from symmetric perfection, and so should his interpreters.